Kepler-421 : A Uranus-sized planet beyond the ice line.

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Kepler-421 : A Uranus-sized planet beyond the ice line.

Post by Sirius_Alpha on 20th July 2014, 8:45 pm

Discovery of a Transiting Planet Near the Snow-Line
http://arxiv.org/abs/1407.4807

In most theories of planet formation, the snow-line represents a boundary between the emergence of the interior rocky planets and the exterior ice giants. The wide separation of the snow-line makes the discovery of transiting worlds challenging, yet transits would allow for detailed subsequent characterization. We present the discovery of Kepler-421b, a Uranus-sized exoplanet transiting a G9/K0 dwarf once every 704.2 days in a near-circular orbit. Using public Kepler photometry, we demonstrate that the two observed transits can be uniquely attributed to the 704.2 day period. Detailed light curve analysis with BLENDER validates the planetary nature of Kepler-421b to >4 sigmas confidence. Kepler-421b receives the same insolation as a body at ~2AU in the Solar System and for a Uranian albedo would have an effective temperature of ~180K. Using a time-dependent model for the protoplanetary disk, we estimate that Kepler-421b's present semi-major axis was beyond the snow-line after ~3Myr, indicating that Kepler-421b may have formed at its observed location.

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Re: Kepler-421 : A Uranus-sized planet beyond the ice line.

Post by Lazarus on 21st July 2014, 4:21 pm

Another interesting result to come out of the HEK project.

Validated from only 2 transits (section 2.6 covers searching for expected transits that would have occurred if the period was an integer fraction of the interval)

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Re: Kepler-421 : A Uranus-sized planet beyond the ice line.

Post by Led_Zep on 22nd July 2014, 4:01 pm

http://spaceref.com/exoplanets/researchers-discover-transiting-exoplanet-with-longest-known-year.html

Kepler-421b is the transiting exoplanet with the longest known year. Kepler-421b circles its star once every 704 days.

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Re: Kepler-421 : A Uranus-sized planet beyond the ice line.

Post by Lazarus on 5th July 2016, 6:20 pm

And then there was a third transit...

Dalba & Muirhead "No Timing Variations Observed in Third Transit of Snow-Line Exoplanet Kepler-421b"
http://arxiv.org/abs/1606.09246

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Re: Kepler-421 : A Uranus-sized planet beyond the ice line.

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